Such a vacuum vessel for treatment of fatty oils is described for example in EP 0 763 082 B1. When producing consumer products as edible oils out of different vegetable or animal oils deodorization is a part of the refining process. During the deodorization the oil is heated to a high temperature 180-275° C. in order to remove contaminants and unwanted substances from the oil. These substances have a lower boiling point than the different triglycerides, which constitute the edible oil. The deodorization is carried through under vacuum 1-20 mbar and the removal of the volatiles is facilitated by adding stripping gas to the oil. The stripping gas may consist of an inert gas or steam. The stripping gas ensures agitation of the oil and promotes heat transfer and makes the removal of the unwanted substances easier.
Vacuum vessels may be used for treatment of many kinds of oils and fats including mineral oil.
For many types of oils it is useful to heat the oil under vacuum with addition of stripping gas during a pretreatment step prior to the deodorization in order to remove the dissolved air and that hinder an oxidation of the oil.
The deodorized oil is also in many cases subjected to a further treatment with injection of stripping gas during a simultaneous cooling after the deodorization step.
The vessel is specially adapted for exchanging heat between incoming and outgoing edible oils in deodorizing and physical refining plants. The incoming oil to the deodorizing column is heated by outgoing oil under vacuum and sparging conditions
The aim of the invention is to increase the efficiency of the heat exchange between the oil and the heating or cooling medium while limiting the size of the vacuum vessel. This is achieved in that the U-tubes for heating or cooling medium are arranged in such a way in said spaces that the flow of oil is counter-current to the flow of heating or cooling medium all through the vessel and that a number of U-tubes are arranged in groups, parallel and in rows above each other.